The age of recipients and the number of received and inseminated oocytes affect the ART outcomes in a transnational oocyte donation program with vitrified oocytes: a single-center, seven-years’ experience

In Italy, egg donation is being allowed again following the ruling by the Constitutional Court n. 162/2014. Nevertheless, the number of voluntary donors is insignificant, probably because no reimbursement is provided. Therefore, the great majority of egg donation cycles are performed by using imported cryopreserved oocytes from foreign countries. However, recent evidence has questioned the overall efficacy of this strategy in comparison with the shipment of frozen sperm and vitrified embryos. A retrospective cohort study was conducted ANDROS Day Surgery Clinic Palermo, Italy in the period 2016–2022, using cryopreserved donated oocytes acquired from a single Spanish clinic (Next Fertility Valencia), with the objective of evaluating the efficiency of each batch of oocytes. The primary outcome was the cumulative ongoing pregnancy rate (COPR). The secondary outcomes were the cumulative clinical pregnancy rate (CCPR) and the miscarriage rate. The COPR totalled 36.8%, the CCPR 49.2% and the miscarriage rate 24.7%. The age of recipients and the number of received and inseminated oocytes were significantly associated with the cumulative ongoing and clinical pregnancies. Thus, the greater the number of oocytes, the higher the pregnancy rate, and the younger the recipients, the higher the success rates. In conclusion, our “transnational” donation program with vitrified oocytes has good success rates. The number of received and inseminated oocytes represents a crucial factor for increasing the cumulative pregnancy rates. Further interesting data regards the negative effect of advancing recipient age on success rates, outlining a possible, important role of age-related uterine factor on implantation mechanisms.